Board: to get on a ship, train, plane, bus, etc. 上船（或火车、飞机、公共汽车等）
The ship was boarded by customs officials.
海关官员登上了这艘船。
Passengers are waiting to board.
乘客们正在候机。

Maintenance: the act of keeping sth in good condition by checking or repairing it regularly 维护；保养 ~ (of sth) uncountable
The school pays for heating and the maintenance of the buildings.
学校负担这些大楼的供热和维修费用。
car maintenance
汽车保养

Turbulence: a series of sudden and violent changes in the direction that air or water is moving in （空气和水的）湍流，涡流，紊流
We experienced severe turbulence during the flight.
我们在飞行中遇到了强烈的气流。

Nightmare: an experience that is very frightening and unpleasant, or very difficult to deal with 可怕的经历；难以处理之事；噩梦 ~ (for sb)
The trip turned into a nightmare when they both got sick.
这次旅行成了一场噩梦，他们俩都病了。
Nobody knows what's going on─it's a nightmare!
谁也不知道是怎么回事 真是棘手至极！ 
Filling in all those forms was a nightmare.
填写了那么多的表格，真是太可怕了。
Losing a child is most people's worst nightmare.
对于大多数人来说，丧子之痛是最可怕的梦魇。

 3/4   首页 上一页 1 2 3 4 下一页 尾页